Pneumatically and manually operated stroboscope



M. T. M CALL June 25, 1957 PNEUMATICALLY AND MANUALLY OPERATED STROBOSCOPE Filed June 27, 1955 2 Sheets-Sheet l INVENTOR.

MARTIN T. Mc CALL June 25, 1957 M. T. M CALL 2,796,793

PNEUMATICALLY AND MANUALLY OPERATED STROBOSCOPE Filed June 27, 1955 2 Sheets-Sheet 2 INVENTOR. MARTIN T. Mc CALL BY v, yak

nited States Patent PNEUMATICALLY AND MANUALLY OPERATED STROBOSCOPE Martin T. McCall, Brooklyn, N. Y. Application June 27,1955, Serial No. 517,980

1 Claim. or. 88-14) This invention relates to stroboscopic devices, and more particularly has reference to a generally improved construction for a device of this nature, characterized by its relative simplicity and capability of being manufactured at a minimum of cost while still insuring anefiiciently operating stroboscope.

Summarized briefly, the present invention includes a flat, circular hollow casing adapted to be conveniently held in the hand. A disc-shaped wheel is rotatably mounted within the casing and the casing and wheel-are provided with sight openings adapted to be brought into alignment with an eyepiece 'on the casing for sighting an object. The casing supports means for imparting rotation to the wheel either mechanically or pneumatically.

One object of importance is to provide a construction, in a stroboscope, which, though of a highly simplified nature, will still permit rotational movement of the wheel at desirably high speeds, thus to provide means facilitating measurement of the speed of a rotating object sighted through the eyepiece.

Yet another object is to provide a device of the character referred to wherein the axle or shaft of the wheel will cooperate with the wheel-rotating kuobin connecting the parts of the flat, circular casing together, the removal of said knob facilitating separation of the component parts of the casing and of the rotating, interiorly disposed portions of the device.

For further comprehension of the invention, and of the objects and advantagesthereof, reference will be had to the following description and accompanying drawings, and to the appended claim in which the various novel features of the invention are more particularly set forth.

In the accompanying drawings forming a material part of this disclosure:

Fig. 1 is a perspective view of a stroboscope formed according to the present invention.

Fig. 2 is a side elevational view of the device as seen from the left of Fig. 1.

Fig. 3 is an enlarged front elevational view in which portions are broken away and other parts are shown in section.

Fig. 4 is a rear elevational view, a part being broken away.

Fig. 5 is a detail sectional view on line 55 of Fig. 3 showing the eyepiece and sight window.

Fig. 6 is a detail sectional view substantially on line 6-6 of Fig. 3, showing the shaft and rotating knob, parts being broken away.

Fig. 7 is a detail sectional view on line 7--7 of Fig. 6.

Fig. 8 is a detail fragmentary perspective view of the wheel and fins.

Fig. 9 is a detail sectional view on the line 99 of Fig. 8.

Fig. 10 is an enlarged detail perspective view of a fin preparatory to insertion into the peripheral slot in the wheel.

Designated generally at 10 there is a fiat, circular casing, including a main portion of cup-like formation, having a The the casing. The casing may be formed of plastic or other suitable material. a I

On the forward edge of the side wall 14 (see Fig. 5) there is a circumferentially extending lip 16. A flat, circular cover 18 of plastic material having an outer diameter equal to that of the main portion of the casing, has a'peripheral recess 20'receiving the lip 16, to'interfit the main portion of the casing and the cover thereof together, thus providing a hollow, closed housing or casing in which is rotatably mounted a stroboscopic wheel 22.

The stroboscopic wheel 22 is shown in the form of a disc shaped from a single piece of sheet metal material. The periphery of the disc is formed with radial lslots'23 spaced equally therearound, and secured in said slotsby welding or otherwise are rectangular flat metal plates or fins 24 extending equal distances on both sides of the plane of the body of the disc as shown in Figs. 8 and 9. The upper surfaces of the fins are flush with the periphery of the disc.

Referring to Fig. 6, formed centrally in the back wall 12 of the casing there is a bearing opening 30, and ex-' tending into said opening is a wheel shaft or axle 32 in the form of a pin having a head 34 at one end. Head 34 bears against the outer surface of back wall 12, while the shank of the pin passes through a center opening 36 formed in the wheel 22 (Fig. 7). Formed integrally with the flat body portion of the wheel, and projecting radially, inwardly of the opening 36, is a lug or key 38, and the shank 32 has a longitudinal groove 40 extending fully from the end of the shank remote from head 34- to a location spaced inwardly along the length of the shank from the head.

Thus, in assembling the parts, one disposes the wheel with its opening ,36 in registration with opening 30, and then inserts the pin 32, with the key and groove in alignment, so that the key moves intothe groove, thus connecting the wheel to the pin for rotation therewith.

Spacers 42, 44, formed as short sleeves, are engaged against opposite faces of the wheel, to space the wheel out of contact with the back wall 12 and cover 18, said spacers loosely engaging against the inner surfaces of the back wall and cover respectively.

The shank projects through a centrally disposed bearing opening formed in the cover 18, into a recess formed in a center boss integrally provided upon a rotating knob 46. A set screw 48 is threadable radially, inwardly of the center boss of the knob, into engagement with the pin 32, thus connecting the knob and pin for conjoint rotation.

By reason of this arrangement, the stroboscopic wheel can be manually rotated, by turning the knob 46.

If desired, the wheel 22 can be rotated by pneumatic means including an elongated, rigid plastic tube 50 inserted through an opening 51 in the side wall 14 as shown in Fig; 3, and communicating at its inner end with the interior of the casing. The tube 50 is extended tangentially to the periphery of the wheel, so that air forced through the tube 50 will impinge against the fins 24, thus to rotate the wheel at a speed which will depend upon the velocity and amount of air forced through the tube.

To force air through the tube, there is provided at the outer end thereof a rubber bulb 52, which is manually squeezed by the user. The bulb, as is usual, has check valve means for the purpose of admitting air thereinto, following evacuation of the air already within the bulb through the tube 50 responsive to squeezing of the bulb.

It will be seen that by rapidly squeezing and releasing the bulb in an alternating sequence, the user can effect a substantially continuous flow of air through the tube 50, into impinging relation with the fins 24, thus to rotate the stroboscopic wheel 22. A discharge outlet 53 is formed in the side wall 14 of the casing for the air so that 'no back pressure is created against 'thefins even'when the wheel is being rotated at its maximum speed. The speed of rotation of the wheel can be varied, by corresponding variation in the intervals between successive squeezings of the bulb.

In the back wall 12, and offset from the center of said back wall, there is a sight window or aperture 54, in registration with an opening 56 formed in the cover 18. An eyepiece 58 is fixedly engaged in the opening 56, and a user, sighting through the eyepiece 58, can view'an object through the window 54.

inwardly of the fins 24, on the wheel 22, there is formed a relatively large opening 69, which is preferably shaped as shown in Figs. Sand 9.

The opening '60 is so positioned on the wheel that on each rotation of the wheel, it will momentarily register with the eyepiece 58 and window 54, so that at this particular point in the rotative movement of the wheel, the object may be observed.

An elongated handle 61 has one end suitably fastened to the casing 10 and extends radially thereof for manipulating the device.

The device is usable in the gauging of the speed of rotation of the object being observed. The user sights through the eyepiece a rotating object, and by steadily increasing the speed of rotation of the wheel 22, ultimately causes the wheel, at the location of the opening 60 thereof, to rotate-at a speed such that the object being observed will appear to be standing still. If desired, calculations can be made whereby the speed of the object being observed can be established. Still further, by making previous calculations as to the number of times the bulb must be squeezed over a particular time interval to establish the speed of rotation of the wheel at a predetermined value, the speed of rotation of the object being observed can be established, by counting the number of times the bulb is squeezed over said time interval, with the wheel being maintained throughout said interval at a rotational speed that causes the object being observed to appearto be standing still.

Another feature of importance, which contributes to the simplicity of the construction and the adaptability-of the same for being manufactured at relatively low cost, resides in the use of the shaft 32 and knob "46' as a means for holding the cover 18 and the cup-like main portion of the casing assembled with one another. Of course,

if desired the cover can be permanently attached to the main p'ortirm of the casing. Alternatively, -peripherally spaced screws can be employed, extending through openings in the cove-r and threaded into recesses formed in the side wall 14. This is considered sufiiciently obvious as not to require special illustration herein.

While I have illustrated and described the preferred embodiment of my invention, it is to be understood that I do not limit myself to the precise construction herein disclosed and that various changes and modifications may be made within the scope of the invention as defined in the appended claim.

Having thus described my invention, what I claim as new, and desire to secure by United States Letters Patent A stroboscope comprising a hollow circular casing having a side wall and front and back walls formed with sight openings, said side wall having a tangentially disposed opening, an axle iournalled in said casing, a wheel secured to the axle to rotate therewith and including a fiat body having an opening registering with said openings on each rotation of the wheel through a 360 cycle, thus to permit sighting of an object through the registering openings of the casing and wheel, said wheel ineluding a circumferential series of fins along the periphery of the body thereof lying in planes extending'transversely of the plane ofithe body, and means on the casing for forcing jets of air thereinto through the opening in the side wall in a direction :such that said air will impinge upon the fins to impart rotative movement to the wheel, said wheel body havinguniformly spaced slots extending radially thereof and opening upon the periphery of the wheel, the fins being engaged in said slots, the fins being of rectangular outer configuration and having their opposite sides-projecting laterally, outwardly in opposite directions from the plane of the wheel body, said fins lying in planes normal to the plane of the wheel body and passing through the axis of wheel rotation.

References Cited in the file of this patent UNITED STATES PATENTS 495,822 Meddins Apr. 18, 1893 731,571 Henry, Jr. June 23, 1903 1,609,233 Whidbourne et a1. Nov. 30, 1926 FOREIGN PATENTS 915,753 Germany July 29, 1954 

